Cockroach inspires robot that squishes down to crawl through cracks and crevices

For most people, the cockroach doesn't inspire anything but the shivers and a mild sense of revulsion. For scientists at the University of California at Berkeley (UC Berkeley), however, the insect has inspired a whole new way of thinking about robots. After studying the way in which roaches squeeze through tiny cracks and crevices, the team developed a robot with similar capabilities.

They might be repulsive to most, but there's no doubt they're impressive examples of animal evolution. In addition to finding that the creepy critters can take the equivalent of 900 times their body weight on their backs, the UC Berkeley team also found that, even when squashed down to one-quarter their size, they can still run remarkably fast.

"What's impressive about these cockroaches is that they can run as fast through a quarter-inch (6 mm) gap as a half-inch (12 mm) gap, by reorienting their legs completely out to the side," says Kaushik Jayaram, the leader of the study. "They're about half an inch tall when they run freely, but can squish their bodies to one-tenth of an inch (2.5 mm) – the height of two stacked pennies."

To develop their robot, called CRAM, which stands for "compressible robot with articulated mechanisms," Jayaram first filmed the roaches using a high-speed camera. This let him see that when roaches flatten themselves out to fit through narrow cracks, they can no longer use their feet to propel them. Rather, they use the sensory spines on the bottom part of their legs (their tibias) to move forward. This is a bit like how, if you were walking on all fours, you'd need to get down on your elbows and use your forearms to move you through a tight space.

"They have to use different body parts to move in these spaces, because their legs and feet are not oriented to work properly," Jayaram says. "But they are still capable of generating the large forces necessary for locomotion, which blew my mind."

Jayaram built a simple robot that uses this technique and, while it can't quite flatten out to the degree the roach can, it is capable of being squished down to half its size while still maintaining forward locomotion. The robot was capped with a plastic shield that was capable of being deformed under pressure, which mimics the roach's exoskeleton, something Jayaram found could smoothly slide past a variety of surfaces, including sandpaper.

The researchers believe robots similar to CRAM could one day help in disaster rescue efforts, such as finding survivors in the aftermath of an earthquake.

"In the event of an earthquake, first responders need to know if an area of rubble is stable and safe, but the challenge is, most robots can't get into rubble," says Robert Full, a professor of integrative biology at UC Berkeley. "But if there are lots of cracks and vents and conduits, you can imagine just throwing a swarm of these robots in to locate survivors and safe entry points for first responders."

This isn't the first time researchers have turned to the roach to help inspire better bots. In fact, just last year, another set of Berkeley researchers took inspiration from the roach's shell to create the streamlined DASH robot, while several years ago, they created a fast-moving insectoid robot called the VelociRoACH.

Till now, it's been said that man's best friend is the dog, but if roach bots start rescuing us after disaster strikes, who knows – maybe the roach will "slip" into that spot, or at least scuttle up a few places.

The team's research was published February 8 online in the journal PNAS.

CRAM can be seen in action in the video below.

Source: UC Berkeley